Archive for December, 2006

Decimating Birds: Episode IV Courting Extinction

29 December 2006

4) Huia (Heteralocha acutirostris)

 

Dead Huia photgraph by John Thomas Pusateri Jr. 2005

The last confirmed sighting of a wild Huia was on a remote New Zealand mountain very nearly 100 years ago, in 1907. All that remains today of this marvellous wattlebird (family Callaeidae) are preserved specimens scattered in museums across the world.

And then there’s the Hamana recording. Made in the 1954(?), some half-a-century after the official extinction date, this is surely one of the most haunting onomatopoems in the world. David Hindley apparently used the Hamana recording as the basis for an appropriately rare recording, Homage to the Huia (1992).

Proverbial fashion victims, the Huia died for their beauty, or at least for the faddish appeal of their bold two-tone tail feathers. Huia feathers were honored as taonga and as such ownership of them was controlled by strict social code.

The abrupt re-arrival of terrestrial mammals, in dugout canoes, dealt a jarring blow to the unique avifauna of New Zealand. Some, like the Moas, were actively hunted to extinction by humans while many more probably succumbed to the onslaught of imported mammalian commensals (rats et al.). By the time William Swainson arrived in New Zealand only three species of wattlebirds occupied New Zealand, the Tieke, the Kokako and the Huia.

Yet, despite the Maori’s less than perfect species conservation record, it seems that Huia populations were stable before European contact, perhaps protected by this rigid social contract of Tapu and Taonga.  Hunters were still able to slaughter them in the hundreds at the end of the 19th century.

Like other wattlebirds, Huia sported colorful fleshy protuberances from their chin. However, Huia are best remembered for their unique form of sexual dimorphism, manifested not in size or plumage but in beak, the male’s thick and scimitar-like, the female’s a slender tapering bow.

The story goes that the male and female worked a cooperative grub-mining operation, the male breaking off large pieces of infested bark, and the female probing burrows and crevices the male could not reach. Although such behavioral partitioning of foraging activity is not uncommon in birds (especially during nesting), such extreme morphological differentiation is unknown in any living species.

Maori legend gave a different explanation for the shape of the female’s beak:

‘Long, long ago, some time after the great canoe migration to Aotea-roa (New Zealand), there was a high-ranking chief who was in the habit of going up into the mountains to set snares for birds. One day when he went to gather in his catch he was surprised to see a strange bird held in one of his snares. Of course, the stranger was the huia.

‘The chief was full of admiration for the beautiful bird he had captured and he plucked two feathers from its tail and wore them in his hair. Perhaps this was the first occasion the huia feathers were worn as a head decoration.

‘Before liberating the huia, the chief bestowed upon it a magic spell and mana (power) with the command that the bird was to appear before him when it was wanted. ‘Now it happened that on one occasion when the chief requested the bird to appear, it was nesting time for the huia and its tail feathers were ruffled and in a bad state. The chief was very angry and asked the bird why its tail feathers were in such a bad condition. The bird told him that it was through sitting on its nest.

‘The chief then said: “I will provide you with a means that will enable you to keep your tail feathers in good order when I next call on you.” He took hold of the huia, which was a female, and bent its beak into a circular shape. He then commanded the huia that every time it sat on its nest, it was to pick up its tail feathers with its circular beak and lift them clear of the nest.’ (Saunders 1968)

Indeed, it was those beautiful tail-feathers that rushed the rare Huia to extinction at the turn of Century 20. Duke of Yorkie, later King George V, went to New Zealand in 1901 riding on steamer(?) he stuck a feather in his cap and sealed the Huia’s fate. The market forces of international fashion swamped the Tapu restraints and within a decade the Huia was gone.

It’s been a good year for fossils, but a bad year for extinction. We seem to have lost the Ivory-Billed again. I continue to mourn the apparent loss of the Baiji, although I anxiously await Darren Naish to reveal some evidence of their cryptic persistence.

Being lately separated from my own mate1, it strikes me that the most tragic moment of extinction isn’t the last breath of the last individual, but his doomed cries as he wanders the forest calling to a mate who isn’t there2.

So here again is the Hamana recording.

UPDATE JUNE 23 2010:

Huia related links, like the birds themselves, have a nasty habit of going extinct. The copies of the Hamana recording that were available online in 2006, have since disappeared. However a video version is available here, for the time being at least.

1- Note the uptick in blog activity, which should cease tomorrow.
2- No. I suppose it is actually that fateful intangible moment where the reproductive capacity of the breeding population ceases to match mortality.

There Goes Concorde Again

27 December 2006

A recent article by Rota and Wagner, at the ‘kick-ass‘ new online journal PloS One, demonstrates that metalmark moths mimic jumping spiders. This ruse apparently helps to protect them from jumping spider predation and may shield the metalmarks from moth-hungry predators too timid or jaded to attack a jumping spider. Rad.

This would seem excuse enough for a salticid (jumping spider) pictorial. Jumping spiders are the most animated, inquisitive, and endearing of arachnids. Some would call them cute. (massive loading ahead..) Read the rest of this entry »

Jethro and Joel were a Choristodere (not a dinosaur)

22 December 2006

Unpublished preliminary sketch for Jethro and Joel Were a Troll by Disney animator and prolific artist/author Bill Peet (Buy the book).



Two-headed choristoderan fossil from Lower Cretaceous rocks in China, from Buffetaut et al. (2006).

The recent publication of the astonishing fossil shown above would seem the perfect end-note to a year packed with crazy, beautiful and marvellous fossils. Axial bifurcation (i.e. two-headedism) in reptiles, especially snakes, is hardly unknown1, but this very young (possibly embryonic) aquatic reptile marks the first recognition of axial bifurcation in the reptile fossil record.

I came across the story over at yet another paleoid blog, Kyle Lindsey’s Παλαιός βίος (that would be “Palaeos Bios” for those of you who went to a school with a draconian anti-Greek policy). Reading the BBC story that Kyle posted first agitated, then exasperated and finally enraged me. Let’s take a moment to tear into the horrendously misleading story, shall we?

Palaeontologists have unveiled the fossilised skeleton of a two-headed dinosaur that roamed the earth about 100 million years ago (MYA).

Nope. Not a dinosaur, Hyphalosaurus (the likely identity of the fossil), was a long-necked aquatic reptile superficially similar to a miniature pleisosaur or a nothosaur but was most closely related to the champsosaurs. The (effing)-champsosaurs were a group of generally large crocodile-esque predatory reptiles that showed up in the Mesozoic and persisted well into the Cenozoic, somehow escaping the K-T(or K-P if you’d rather) mass extinction.

This is not simply a semantic distinction. “Dinosaurs” were a distinct group (or possibly two or more distinct groups) that shared a set of features not found in other Mesozoic reptiles. Any writer covering paleontology should take the time to figure this out. Would editors tolerate a journalist who lazily referred to all legislative bodies as “The U.S. Senate” or called Cambodians “Chinese”?

While the exact age of the formation this fossil came from is in debate, it’s probably more like 120 million years old, but who’s counting? Unfortunately the BBC article gets worse:

But before it is added to the pantheon of prehistoric beasts occupied by luminaries such as Tyrannosaurus Rex and Triceratops, scientists point out the dinosaur was only 70mm tall and died at a very young age.

What does this have to do with anything? Only large taxa earn a place in “the pantheon”? I won’t even waste time on the misformatting of the scientific binomials, but it should be “Tyrannosaurus rex and Triceratops”.

Publishing their findings in the Royal Society journal, the Chinese palaeontologists discovered the specimen in the famed dinosaur-stamping grounds of Yixian Formation in the north-east of the country, with its mixture of volcanic and sedimentary rocks an ideal place for fossils to be preserved.

Okay maybe a run-on sentence, but I’m probably not one to throw stones here. There certainly are fantastic dinosaur fossils from the Yixian although in this context describing the Yixian formation as “dinosaur-stamping grounds” probably perpetuates the misidentification.

They explain that the fossilised remains of the infant, possibly an aquatic diapsid such as Sinohydrosaurus lingyuanensis or Hyphalosaurus lingyuanensis, is the first time that axial bifurcation – where reptiles develop two heads and necks – has been observed in dinosaurs.

Still not a dinosaur. And given that Sinohydrosaurus is regarded as junior synonym for Hyphalosaurus2, it’s either Hyphalosaurus or something else. Worth noting, is that Hyphalosaurus is a relatively abundant vertebrate fossil, widely (and illegally) exported from China for purchase by private collectors. The fossils range in size from a few centimeters to over a meter, apparently representing the organism at all stages of development. Many of the fossils, like Jethro and Joel, appear to be juveniles or even embryos.

It’s rare to get such a complete growth series in fossil vertebrates, making Hyphalosaurus a wonderful candidate a detailed analysis of growth and development patterns (someone may well be working on this already). It’s even plausible that other malformed specimens might be out there. Moving along…

The condition occurs relatively commonly in turtles and snakes as a result of the species’ regenerative qualities when suffering an embryonic lesion.

Most explanations of axial bifurcation in reptiles cite an incomplete duplication of the embryo, similar to mechanism that yields conjoined twins in humans. This is the first I’ve read of lesions, but it’s an interesting idea. I’d like to know more.

Many extraordinary fossils from the Yixian Formation have later been exposed as fakes, but the scientists from the Shenzen Palaeontological museum insist the fossilised remains of the infant, which would have grown to 1m long, are genuine.

While a heavy dose of skepticism is appropriate for such a bizarre fossil, this closing paragraph is not just misleading, it provides (possibly unknowingly) some prime creationist fodder. As far as I know only one fossil from Liaoning was exposed as a chimerical forgery, the infamous Archaeoraptor. That’s hardly “many” and calling it a “fake” obscures the fact that the theropod-half of Archaeoraptor a.k.a. Microraptor is both real and exceptionally important to science (as is the bird-half Yanornis).

Perpetuating the misconception that paleontologists are frequently duped by abundant fossil forgeries is inexcusable.

While Archaeoraptor was cobbled together from pieces of different animals, Jethro and Joel appear to be in one piece of matrix and the close association of the necks and heads strongly suggest it to be genuine.

Okay, so that was an exercise in futility. Is it too much to ask that journalists covering science to at least a little bit of background research? A simple scanning of the Wikipedia Hyphalosaurus entry would have made it apparent that the animal wasn’t a dinosaur. And turing one fossil forgery into “many fakes” is both foolish and dangerous.

Well, at least I put off Christmas shopping for a few more hours. Maybe I’ll just order one of these for everyone on my list:

Postscript: HMNH has a brilliant P. T. Barnum-style post on Jethro and Joel. The Neurophilosopher uses J&J as the jumping off point for a fascinating account of lab-made double-headers, go read it now.

 

1- While I’m generally very wary of mixing science and mythology (it seems generally to wind up doing a disservice to both), it seems at least plausibile that bicephalic snakes or lizards might have been the inspiration for various multi-headed reptiles of myth, like Lotan, Orochi, the Lernaean Hydra and the Dragon of Revelation. Then again, maybe the seven-headed Dragon described in Revelation 12:3 is the E.U., or Russia or China or whatever (and maybe Mongolia is the dreaded Turquoise Pupa of Evil).

2- The double-naming of Hyphalosaurus is an interesting story. Two different groups of Chinese researchers simultaneously described (apparently unknowingly) the part and counter-part of the same fossil thus generating two competing names. The charmingly straight-forward Sinohydrosaurus (literally “Chinese water lizard”) was published slightly later and thus yields to the slightly more prosaic Hyphalosaurus (“submerged lizard”). A brief technical account from the of the mix-up from the Journal of Vertebrate Paleontology is available as a pdf, Smith and Harris (2001) .

Where Has All the Carrion Gone?

20 December 2006

It’s rather easy to overlook the dead, they don’t move much and they hardly have anything to say. Nevertheless, it’s an apparent truism that there are not enough bird carcasses lying around, compared to the shitstorms of flocking pigeons, starlings, spugs and whatever other avian excretory plagues defile our coveted personal transport systems. AÖrstan recently parsed this question over at Snail’s Tales.

One explanation for the dearth of dead bird carcasses rests upon the ability of necrophages to quickly process latent biomass into food. There is undoubtedly much truth to this, and I loath to think of wading through a world without scavangers and decomposers.

The Snail’s Tales post led me to A Snail’s Eye View of dipteran remediation complete with some beautiful fly graphics of calliphorids that “appear from nowhere” (spontaneous generation!) and the aptly named sarcophagids like those fornicating on the shovel handle above.

I argue that this is only part of the story.

Anyone who hikes with dogs is aware that there is no shortage of carrion in various states of rereification out there:


Though we were able to keep Clyde from downing the above wriggling protein-fest, he soon arrived with another partially decomposed rodent proudly clenched in his jaws. He also rustled up some quasi-disarticulated Mule Deer limbs on the same hike. I probably ought to chalk up my queasy GI sentiments about eating carrion not to any moral superiority on my part, but to Clyde’s superior constitution1.

Early on, it would seem that Homo was an opportunist par excellence, surely not shying away from a free meal. Yet somewhere along the way tools or culture or behavior weakened our stomach and we lost the taste for a nicely ripened marmot carcass with good maggot marbelling.

How exactly our digestive weakness, or disgust, got cross-mapped across onto our regard for various “non-normative” sexual behaviors will be the territory for future enlightened generations of neuro-historians2, and perhaps also the subject of a few well earned chuckles, though I’m betting it had something to do with death and maybe Catholics.

Anyway, anyone with open eyes is likely to observe a number of dead birds across their daily transects whether in city or country3. On a recent trip down I-5 I counted no fewer than six dead owls, mostly Tyto alba probably. Carel accounts 27 dead Longears along a Nevada highway and I wonder how many I missed. There are many dead raptors to be seen along our “rights-of-way” drawn in no doubt by the car-killed carrion buffet and perhaps by the unintentional baiting of rodents et al. by cast off tasty morsels.

Birds fly, make noise, aggregate in large numbers…they’re remarkably conspicuous animals. It’s notable that there are a lot more birders out there than mousers or lizarders or spiderers. But when they die they’re a bit more crytpic.

I imagine that the main source for the discrepancy is our general disregard for the dead animals we step over and around everyday without a second thought. A flattened Rock Dove is much easier to overlook than one flapping about. We generally don’t go hunting for the thousands of half-rotten starlings littering our alleys and gutters and chimneys so we should be wary of assuming their absence.

1- Of course, Clyde is no stranger to pleasures of the hunt. Moments after I took the top photo, and seconds after frolicking joyfully in the surf,

Clyde stalked and killed the first of two vertebrates he’s dispatched in the eight months since we’ve had him. The victim was a shorebird probably much akin to the mummmy found in the sand. I don’t think it was a Snowy Plover. Still, I feel terrible about it.

2 – Note the optimism.

3 – Please, I spelled it properly, check again.

Just Checking In…

18 December 2006

If you’ve been chatting with vertebrate paleontologists at cocktail parties in the last week or so, chances are good that the two unlikely critters pictured below were mentioned:


Miocene mammal jaw fragment from New Zealand(!), Worthy et al. 2006 (left) and reconstruction of Volaticotherium antiquum a MESOZOIC gliding mammal from Mongolia by Chaung Zhao and Lida Xing, Meng et al. 2006 (right).

At left is the as-yet undescribed mammal of “unknown relationships” from New Zealand. That’s right, apparently that purportedly mammal free avitopian sliver of Gondwana had some furry stowaways that eked out a modest survival at least into the Miocene. More on this if I ever get around to posting on the Huia (decimated bird number four for those still counting). Especially intriguing is that the bones appear to belong not to a placental or marsupial or even a monotreme, but to an extinct group of archaic mammals with roots deep in the Mesozoic.

At right is the remarkable Volaticotherium antiquum1, “ancient airborne mammal”, a Mesozoic mammal which apparently employed a patagial membrane to glide between trees much like the familiar flying squirrels (Pteromyini), as well as more esoteric mammalian gliders like the colugo and the sugar glider. This pushes the record of gliding mammals back by about 70 million years and provides yet one more blow to the misconception of Mesozoic mammals as uniformly unremarkable shrewoids. Worth noting is the volaticotheres insectivorous dentition, more on that too later. Maybe.

I always saw GW as more of the Bullwinkle type…

Once upon a time, microecos was going to keep abreast of the publication of notable vertebrate fossils complete with vaguely insightful quasi-scientific analysis. Alas, the pace of discovery in 2006 proved well beyond my means. Fortunately a number of other weblogs already fill that gap (without the vagueness etc. of course).

Michael Ryan’s Palaeoblog is one-stop shopping for the late-breaking paleonews, illuminated with vintage comics covers. Palaeoblog has posts on both the new New Zealander, and the Mesozoic glider.

HMNH also has a post on the glider, and a very interesting discussion of the New Zealand fossils with respect to “ghost lineages”, a concept with close ties to the more popularly parlayed “living fossils” of the last post (remember, the bit from last September with the naked lady? Oh yeah it’s down there).

Darren Naish also writes a bit about both on his highly anticipated recent post about mid-continetal seals. If you make a paypal pledge maybe he can be convinced to stop taunting us like that.

All three blogs are mandatory reading for those not wishing to make ignorant asses of themselves at their next social drinking engagement with paleontologists, although you probably will anyway.

1 – Note the old-school Latinate name, bucking the recent trend of borrowing from languages local to the discovery site.

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